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Design and realzation of electric measurements on biological tissues
Kocová, Lucie ; Palai-Dany, Tomáš (referee) ; Tománek, Pavel (advisor)
This master’s thesis is focused on the electrical properties of biological tissues and flesh in particular. Their electrical characteristics depend on the physical and chemical parameters that determine the concentration and mobility of ions in metabolic fluids. From the electrical point of view, flesh can be simply substituted by a field of elongated conductive cells which are separated by the insulating membrane from each other. In the next part, the Fricke model is introduced. The model describes the measurement of impedance of the tissue at low and high frequencies. The aim of the work is to assess how the impedance of the dielectric sample is dependent on the frequency of the electrical signal during the optimal aging or ripening of flesh.
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Scanning photoelasticimetry
Šikula, Radek ; Palai-Dany, Tomáš (referee) ; Škarvada, Pavel (advisor)
This thesis deals with the polarization of the light and its use in the field of photoelasticity measurement. The theoretical part is divided into two sections. First the light is described as electromagnetic waves in the theoretical section. Further the polarization types are described and the principle of the photoelasticity is explained. Electronic is described in the second section of the theoretical part. In the frame of the experimental part electronic design is presented together with the program for the scanning device controller. The functionality of the device is tested in the last section.
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Time-domain Dielectric Spectroscopy of Carboxymethylcellulose
Palai-Dany, Tomáš ; Lelák, Jaroslav (referee) ; Mentlík, Václav (referee) ; Liedermann, Karel (advisor)
The dissertation deals with the time-domain dielectric relaxation spectroscopy of carboxymethylcellulose. The main attention was paid to the experimental part of research, mainly to the design and subsequent development of an experimental setup for the measurement of discharge currents and for their processing and analysis. The subject of the measurement is carboxymethylcellulose (CMC), which is a simple polysaccharide used in wide range of applications, among else also in biomedical engineering. The study of CMC properties has required the development of a new experimental set-up of original design, which includes the equilibration (short-circuiting) of a sample before the measurement, charging and discharging at defined time intervals, switching between these two modes, recording of measurement, adjustments and processing of measured signals up to Fourier transformation into the frequency domain and, finally, calculation of complex permittivity of the sample. The frequency dependence of complex permittivity or its imaginary part, obtained by Fourier transformation of discharge current in time domain, is then referred to as the dielectric spectrum. In view of the fact that current measurements were done at very low levels of measured signal (below 10-12 A) the whole measurement was no easy matter. The framework of the work also necessitated studies and subsequent resolution of problems associated with shielding, grounding, presence of noise and sensitivity to various ambient influences. The research work focused on a reliable and trustworthy measurement of very low discharge currents and, subsequently, mathematical processing of noise present in them, i.e., operations with the original, experimentally established signal in time domain, leading in principle to a digital filtration of measured dielectric data. A further pursued objective is the explanation of dielectric parameters of tested carboxymethylcellulose sample in the widest possible frequency spectrum. The integral part of the research was the selection and application of the method for the transformation of the adjusted signal to the frequency domain. The experimental works, including data processing, were carried out in the Department of Physics, Brno FEEC BUT. Measurements were done with Keithley 617 Electrometer, HP4284A Frequency Analyzer and Janis CCS-400-204 cryogenic system. The results were completed with results obtained at the V Department of Experimental Physics, Centre for Electronic Correlations and Magnetism, University of Augsburg, Germany.
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Quantum efficiency measurement of optoelectronic components and development of experimental equipment
Lipr, Tomáš ; Palai-Dany, Tomáš (referee) ; Macků, Robert (advisor)
This thesis deals with the issue of quantum efficiency measurement of optoelectronic devices. The physical nature of silicon solar cells is explained here. In addition, the quantum efficiency as a concept is introduced. There is also discussed the influence of a solar cell semiconductor structure on the quantum efficiency itself. Furthermore, the thesis is focused on the design of an experimental set-up for automated measurement and data acquisition. The final realization of the step motor control unit is described in detail. It includes local and/or remote operations, design and development motivation. The next chapter is dedicated to analysis of the Matlab source code for remote operation, data acquisition and presentation. The final part of the thesis gives attention to experiments with real structures, not only the solar cells. The obtained results of analyzed measurements are presented at the conclusion.
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Time-domain Dielectric Spectroscopy of Carboxymethylcellulose
Palai-Dany, Tomáš ; Lelák, Jaroslav (referee) ; Mentlík, Václav (referee) ; Liedermann, Karel (advisor)
The dissertation deals with the time-domain dielectric relaxation spectroscopy of carboxymethylcellulose. The main attention was paid to the experimental part of research, mainly to the design and subsequent development of an experimental setup for the measurement of discharge currents and for their processing and analysis. The subject of the measurement is carboxymethylcellulose (CMC), which is a simple polysaccharide used in wide range of applications, among else also in biomedical engineering. The study of CMC properties has required the development of a new experimental set-up of original design, which includes the equilibration (short-circuiting) of a sample before the measurement, charging and discharging at defined time intervals, switching between these two modes, recording of measurement, adjustments and processing of measured signals up to Fourier transformation into the frequency domain and, finally, calculation of complex permittivity of the sample. The frequency dependence of complex permittivity or its imaginary part, obtained by Fourier transformation of discharge current in time domain, is then referred to as the dielectric spectrum. In view of the fact that current measurements were done at very low levels of measured signal (below 10-12 A) the whole measurement was no easy matter. The framework of the work also necessitated studies and subsequent resolution of problems associated with shielding, grounding, presence of noise and sensitivity to various ambient influences. The research work focused on a reliable and trustworthy measurement of very low discharge currents and, subsequently, mathematical processing of noise present in them, i.e., operations with the original, experimentally established signal in time domain, leading in principle to a digital filtration of measured dielectric data. A further pursued objective is the explanation of dielectric parameters of tested carboxymethylcellulose sample in the widest possible frequency spectrum. The integral part of the research was the selection and application of the method for the transformation of the adjusted signal to the frequency domain. The experimental works, including data processing, were carried out in the Department of Physics, Brno FEEC BUT. Measurements were done with Keithley 617 Electrometer, HP4284A Frequency Analyzer and Janis CCS-400-204 cryogenic system. The results were completed with results obtained at the V Department of Experimental Physics, Centre for Electronic Correlations and Magnetism, University of Augsburg, Germany.
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Scanning photoelasticimetry
Šikula, Radek ; Palai-Dany, Tomáš (referee) ; Škarvada, Pavel (advisor)
This thesis deals with the polarization of the light and its use in the field of photoelasticity measurement. The theoretical part is divided into two sections. First the light is described as electromagnetic waves in the theoretical section. Further the polarization types are described and the principle of the photoelasticity is explained. Electronic is described in the second section of the theoretical part. In the frame of the experimental part electronic design is presented together with the program for the scanning device controller. The functionality of the device is tested in the last section.
|
|
|
Design and realzation of electric measurements on biological tissues
Kocová, Lucie ; Palai-Dany, Tomáš (referee) ; Tománek, Pavel (advisor)
This master’s thesis is focused on the electrical properties of biological tissues and flesh in particular. Their electrical characteristics depend on the physical and chemical parameters that determine the concentration and mobility of ions in metabolic fluids. From the electrical point of view, flesh can be simply substituted by a field of elongated conductive cells which are separated by the insulating membrane from each other. In the next part, the Fricke model is introduced. The model describes the measurement of impedance of the tissue at low and high frequencies. The aim of the work is to assess how the impedance of the dielectric sample is dependent on the frequency of the electrical signal during the optimal aging or ripening of flesh.
|
|
|
Quantum efficiency measurement of optoelectronic components and development of experimental equipment
Lipr, Tomáš ; Palai-Dany, Tomáš (referee) ; Macků, Robert (advisor)
This thesis deals with the issue of quantum efficiency measurement of optoelectronic devices. The physical nature of silicon solar cells is explained here. In addition, the quantum efficiency as a concept is introduced. There is also discussed the influence of a solar cell semiconductor structure on the quantum efficiency itself. Furthermore, the thesis is focused on the design of an experimental set-up for automated measurement and data acquisition. The final realization of the step motor control unit is described in detail. It includes local and/or remote operations, design and development motivation. The next chapter is dedicated to analysis of the Matlab source code for remote operation, data acquisition and presentation. The final part of the thesis gives attention to experiments with real structures, not only the solar cells. The obtained results of analyzed measurements are presented at the conclusion.
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